In the realm of communications, there are few things that one can do that can convey so much meaning, yet require so little effort. Add a simple "RT" to a tweet, or hit the little retweet button in any Twitter client, and you elevate 140 characters that might otherwise slip by unnoticed to another level, a level that, at the very least, you're saying is worth your followers' attention.

Retweeting is so easy that many people hardly think about what it means, and barely recognize that what they're doing, quite literally, is republishing someone else's thoughts.

Most of the time, that's a totally benign action, but what if the original tweet was an attack on someone? Or worse, a malicious and dishonest accusation?

There's no doubt that someone who pens an original tweet can be sued if they libel or defame someone else, just as if they'd published in a newspaper or magazine. Witness the lawsuit against rocker Courtney Love for some ill-considered tweeting. And in England, thousands of people are facing recriminations for tweeting a BBC story that mistakenly linked a government official to sexual abuse of a child. But is there legal liability for retweeting something libelous or defamatory?

The answer is complicated.

According to Jennifer Granick, the director of civil liberties at the Stanford Center for Internet and Society, retweets are little different from any other form of communication. Translation: a libelous or defamatory retweet can absolutely expose its sender to legal liability. But as is the case with other media like newspapers or books, intent is everything.

"There's nothing special about a user retweeting," Granick said. "If the original is defamatory, the retweet is too. But the plaintiff has to meet the malice element for each defendant. In other words, if the retweeter didn't know it was false, she's not liable."

Given how little time or thought it takes to retweet, one can safely assume that the vast majority of potential cases don't meet the malice standard and that generally, the most a retweeter could be found guilty of is having had the bad taste to forward on someone else's questionable tweet.

But not everyone is sure that it's that simple.

"As a republication, I think the answer is yes," Erik Syverson, a Los Angeles attorney who specializes in Internet law said of whether retweeting can be libelous. "If someone republishes a defamatory statement, they could have secondary liability."

At its core, libel is a false statement of fact, and the best defense is an absence of malice, as Granick explained. But Syverson suggested that simply being unaware that a retweet contained false information may not in itself be enough protection against an expensive judgment. Twitter users may well want to take proactive steps to shield themselves from liability. For example, he said, adding some type of disclaimer to their Twitter user profile along the lines of "anything retweeted is not adopted as a statement of fact" could be helpful. "In other words, you don't endorse the view in any way," Syverson said, and "it's only opinion."

Like many Twitter users, CNET reporter Daniel Terdiman offers a disclaimer in his Twitter profile noting that retweets do not constitute an endorsement.
Daniel Terdiman/CNET

Indeed, more and more Twitter users are adding such disclaimers to their profiles, partly in hope, it would seem, of being able to retweet freely. Others add such a disclaimer to give themselves the freedom to retweet things they don't agree with but which they want the world to see.

Even that may not be enough, however, given how much more visible someone's tweet is than their user profile. To Virginia Sanderson, an associate attorney at Kronenberger Rosenfeld in San Francisco, people would be wise to make it clear directly in the text of their post that they are simply retweeting from a prior source and that they haven't ascertained the truthfulness of what was originally said.

That's similar to language often seen alongside traditional journalistic editorials stating that an op-ed is the viewpoint of the writer and not necessarily the publication. "I don't think simply putting something in their profile is going to suffice," Sanderson said. "Because it's all about who views the defamatory tweet. Would they be expected to [look at the user's profile]? I don't think so."

The problem with Sanderson's solution, of course, is that there is often little room left within the 140 character limit of a tweet to add any kind of disclaimer to a retweet. Plus, the retweet button in Twitter's official apps don't offer any way to make edits before sending, although other apps sometimes do.

The truth is, none of the attorneys contacted for this story were aware of any specific cases where someone had been sued in the United States for the contents of a retweet. And that would suggest that the chances of facing legal liability for such behavior on Twitter is extremely low.

But that could change. And given the cost of lawyers' time, no one wants to be forced to defend themselves even if they are on the right side of the law. After all, if someone decides to sue you, you might need to pony up thousands of dollars, even as much as $20,000, to retain a decent attorney just to fend off the suit. And these days, the courts are awash in lawsuits filed by people who, rightly or wrongly, feel they've been defamed online.

"Defamation has just exploded in the last five years," said Syverson. "It's just insane, with user-generated content. It's the golden age of defamation."